Some issues that need to be addressed:

   *  The various underlying packages come with different licenses. These should be properly documented.
   *  Not all libraries are threadsafe. This is certainly true (by the current implementation) for those libraries that take user-defined functions as arguments.
   *  The current implementation may or may not gracefully handle user-defined procedures in a different namespace than the global one.
   *  There is also the issue of the required run-time libraries - specifically a problem on Windows. Easiest is to put these libraries in the same directory as the  package.